Carburetor



Dc. 30, 1941. T g csso 2,267,722.

CARBURETOR Original Filed May 14, 1936 2 Shee ts-Sheet l [Nve 72 I Dec. 30, 1941. H. E. T. ERICSSON GARBURETOR Original Filed May 14, 1936 2 Sheets-Sheet 2' I i I Patented Dec. 30, 1941 GARBURETOR Harald Eugen Theodor Ericsson, Ncrrkoping, Sweden Continuation of application Serial No. 79,787, May 14, 1936. This application June 21, 1939, Serial No. 280,391. In Sweden May 10, 1935 3 Claims.

The present invention relates to carburetors and more particularly pertains to an arrangement for producing a driving agent or fuel mixture for internal combustion engines. This is a continuation :of my co-pending application Serial No. 79,787 filed May 14, 1936.

In the production of fuel mixtures for internal combustion engines it is important that the suction air be supplied not only with atomized fuel but also with a suitable amount of fuel in the vapor phase. The proportion betWen air and vapor should then be such that the combustion in the cylinder can be initiated through an exa mixture of air and atomized fuel being brought into contact with the hot body in such manner that air and fuel are simultaneously heated resulting in the conversion of part of the fuel into vapor. A carburetor operating in this manner gives an uncontrollable fuel mixture which varies considerably with the conditions of operation, the fuel mixture becoming in some cases too rich in fuel and too poor in air with attendant incomplete combustion and dilution of the lubricating oil in the engine with unburntv fuel, and in other 1 cases an insufficient filling of the engine cylinders is obtained on account of the air and vapor being heated to too high a temperature.

The present invention has for its object to is substantially characterized by the fact that the fuel, without preceding mechanical atomization, is first vaporized by being spread out in the form of a fuel film on the surface of a body which is heated by means of exhaust gases or mother 7 manner, over which fuel film the suction air is passed so as to take up fuel in the vapor phase. whereafter fuel in atomized or finely divided con dition is supplied to the gas mixture obtained through the vaporization.

The invention differs essentially from previously known methods in that the vaporizing step constitutes the initiating step in the production of the fuel mixture. The advantage is thus gained that the air is dry when it takes up the avoid the above-mentioned inconveniences and 1* fuel vapor, dry air having a greater capacity of taking up vapor than air which is mixed with fuel particles formed through atomization since such fuel particles tend to promote condensation of already vaporized fuel. In carrying out the invention the fuel, without a preceding mechanical subdivision, is spread in the form of a fuel film over the surface of the heated body and the advantage is gained in that the suction air is practically insulated from the heated body by the fuel film, so that the air is not subjected to over-heating through direct contact with the hot body but is heated substantially only through the intermedium of the fuel Vapor at the comparatively low temperature of the latter.

The invention is hereinafter described in detail with reference to the accompanying drawings which by way of example shows an embodiment according to the invention of a carburetor adapted to be applied to an ordinary engine designed for gasoline operation. In the drawings:

Figure 1 is a vertical section through the carburetor device and its appertaining float housing according to a first embodiment.

Figure 2 is a cross-section on the line 2-2 in Figure 1.

Figure 3 is a partial section on the line 3-3 in Figure 2.

Figure 4 is a vertical section taken perpendicularly to the section shown in Figure 1.

Figure 5 is a cross-section on the line 55 in Figure 4.

According to the embodiment illustrated in Figures 1 to 5 the carburetor is provided with a hollow substantially ball-shaped heating body I which is adapted to be internally heated by means of the exhaust gases of the engine and to be externally flushed over by the air of combustion. The fuel is supplied to the space 23 from the distribution chamber l3 as hereinafter described in such a manner as to be spread out, without preceding mechanical subdivision, in the form of a film on the external surface of the heating body I by the aid of the current of air of combustion. By means of tube sockets I extending from the heating body the latter is connected with the exhaust pipe of the engine so that the exhaust gases will flow through the heating body, the gas passage consisting of four hollow spaces or channels 2, which are mutually separated by intersecting walls 3. The walls 3, which are shown with streamline-shaped cross section, have for their purpose to enlarge the heat absorbing surface of the body I and to distribute the absorbed heat uniformly over the heating body. In this manner it is possible to obtain a uniform heating of the fuel film during its passage over the surface of the body I.

During its travel over the heat delivering body the coherent fuel film receives the heat necessary for vaporization of the fuel and gives off vapor to the inlet air, the film insulating the inlet or suction air from the heat source so that the air-vapor mixture obtains only a comparatively low temperature which is controlled by the' vaporating point of fuel. On account of said temperature control a fuel-vapor mixture of the greatest possible density is obtained which is of considerable importance both for obtaining complete combustion in the engine and for obtaining a good filling of the cylinders.

In case all the fuel should not be vaporized during its travel over the heating body the fuel film will finally reach a neck-shaped portion 4 on the body I which portion terminates in a sharp edge 5 extending in the transverse direction of the air current, at which edge the fuel film is mechanically sub-divided or atomized by the air current and intimately mixed with the latter. For the purpose of insuring said mechanical subdivision, the air passage is constricted at the neck 4 by means of a choking ring 6. Said ring is preferably exchangeably inserted in the connecting pipe I of the carburetor in which pipe a throttle 8 is arranged. The throttle is mechanically connected by means of a link 9 with a slide valve I guided in a central bore in the body I, said valve being adapted to regulate the supply of fuel to the carburetor. The lower end of the slide valve constitutes the valve body proper which cooperates with a number of small preferably calibrated ports II in a sleeve I 2 which is inserted in a threaded wall of a neck-shaped portion merging to the lower portion of the heating body. Between the sleeve I2 and the walls of the bore is arranged a cylindershaped distribution chamber I3 from which on account of the sucking action of the engine the fuel is brought to the outside of the body I through ducts I4 which are evenly spaced around the neck portion. The fuel can be supplied to the cylinder-shaped distribution chamber I3 from the outlet duct I5 of the fioat chambers in different paths, namely on the one hand through the lower mouth of the sleeve I2, which is shaped to form a valve seat for an adjustable needle valve I6, and then further in dependence of the position of the slide valve II] through one or more of the ports II in the wall of the sleeve, on the other hand through a valve opening I8 wh ch is provided especially for no-load running and is adjustable by means of a needle valve I1 and from said opening through a duct Il9 directly to the distribution chamber I3.

The suction air of the engine enters through an air intake 20, Figure 4, which is arranged in ordinary manner and comprises a spring-loaded damper 2| which is opened more or less in dependence of the degree of evacuation in the suction pipe. From the intake 20 the air passes through a chamber in the lower portion of the carburetor and continues past a choke ring 22, which is disposed at the point where the ports I4 open into the air passage, and on to the vaporizing chamber 23 proper in which the heating body I is positioned. The space 23 is surrounded by walls which follow the shape of the heating body at a suitable distance'from the latter and are joined to the connecting pipe 1 of the carburetor. The cross sectional area of the vaporizing chamber should be of about the same order of magnitude as the corresponding area of the suction pipe of the engine.

At idle running and low engine load it may be desirable to increase the air velocity at the mouths of the fuel outlet ports I4 beyond the value obtainable by means of the choke ring 22. For this purpose there can be provided an adjustable air accelerating device. Said device can, for example, as shown in Figures 1, 2 and 4, consist of a movably arranged sleeve 24 which is so shaped and arranged, that in the position shown in the drawings corresponding to the position of idle running said sleeve, in cooperation with the choke ring 22, blocks the greater part of the cross sectional area available for the flow of air so that the air current will have to pass through a narrow passage between the sleeve and the lower neck portion of the heating body I. When the engine is loaded the sleeve 24 is shifted to the position 24 marked in dotand-dash lines in which its choking action ceases. By making the sleeve comparatively light and by arranging it to open against the action of a preferably tensioned spring 25 the air current can be utilized for automatically shifting the position of the sleeve. During the shifting movement the sleeve is guided by double-bent metal wires 28 which bear on the ring 22 and the lower ends of which are connected with a guide ring 2'! slidable on the lower neck portion of the heating body I, said guide ring being also arranged to take up the pressure of the spring 25.

Since in the carburetor according to the invention the air velocity and the amount of sup- Dlied fuel are controllable within wide limits both when the engine is running idle and when it is loaded and since the heating body I can be given any desired temperature as by means of a simple damper disposed, for instance, in the exhaust pipe connected to the carburetor, the carburetor can be used for all engine fuels available on the market; even while in operation the carburetor can be switched from one fuel to another. Furthermore, there is obtained through the temperature regulation a possibility of adapting, during operation, the temperature in such a manner that the fuel is partially vaporized during its passage over the heating body while the rest of the fuel is mechanically subdivided by means of a mechanical atomizing device (edge 5 on the upper neck portion of the body) arranged in immediate connection with the heating body.

The carburetor illustrated is provided with two separate float chambers 28 and 29 intended for different fuels. The fioat chambers each contain a float 30, 3'! which by means of levers 32, 33 actuate valves 34, 35 in the fuel supply line from the respective fuel tanks. The float chambers 28 and 29 communicate each through an appertaining duct 36 and 31 respectively with the common outlet duct I5 previously referred to. In the ducts 36 and 31 are arranged valves 38 and 39 respectively which are shiftable by means of a key 40, preferably operable from the drivers seat, in such a manner that only one valve can be opened at a time.

I claim:

1. In a carburetor having an air passage provided with an air inlet and having an enlarged portion and anoutlet, a member having a fuel inlet extending across'the air passage, a heated hollow body arranged in the enlarged portion of said passage and extending from said member towards the outlet of the passage, said member having ducts communicating with the fuel inlet and terminating adjacent an end of the heated body so as to cause the fuel to spread as a film over the surface thereof whereby the film will be flushed over by the air to move the same towards the outlet, a choke ring arranged in the air passage adjacent the other end of the heated body, the end portion of the heated body adjacent said choke ring having an end surface extending at a substantial angle to the movement of the air through said passage and providing an angular edge over which the fuel film is whirled by the action of the air adjacent the choke ring, and the inlet and the outlet and the heated body being arranged co-axially of each other.

2. In a carburetor having an air passage provided with an air inlet and having an enlarged portion and an outlet, a member having a fuel inlet extending across the air passage, a heated hollow body arranged in the enlarged portion of said passage and extending upwardly from said member, said member havingducts communicating with the fuel inlet and terminating adjacent the lower end of the heatedbody so as to cause the fuel to spread as a film over the surface thereof whereby the film will be flushed over by the air to move the same towards the outlet, a removable choke ring arranged in the air passage adjacent the upper end of the heated body, the end portion of the heated body adjacent said choke ring having an end surface extending transversely to the normal movement of the air through said passage and providing an angular edge over which any residue of the fuel film is whirled by the action of the air adjacent the choke ring, and the inlet and the outlet and the heated body being arranged coaxially of each other.

3. In a carburetor having an air passage provided with an air inlet and having an enlarged portion and an outlet, a member having a fuel inlet extending across the air passage, a heated hollow body arranged in the enlarged portion of said passage and extending from said member towards the outlet of the passage, said member having ducts communicating with the fuel inlet and terminating adjacent an end of the heated body so as to cause the fuel to spread as a film I over the surface thereof whereby the film will be flushed over by the air to move the same towards the outlet, a choke ring arranged in the air passage adjacent the other end of the heated body, the end portion of the heated body adjacent said choke ring having an end surface extending at a substantial angle to the movement of the air through said passage and providing an angular edge over which the fuel film is whirled by the action of the air adjacent the choke ring, the inlet and the outlet and the heated body being arranged coaxially of each other, means for storing two types of liquid fuel adjacent said member, and means for selectively admitting either of said fuels to said fuel inlet.

HARALD EUGEN THEODOR ERICSSON. 

